Question

find the value of K if x+2 is a factor of 3x^2+Kx+6

Answer 1

as x+2 is a factor, remainder need to be zero

x+2=0

x=-2

substitute in the equation

3(-2)^2+k(-2)+6=0

3(4)-2k+6=0

2k=12+6

2k=18

k=9

Answer 2

as x+2 is a factor, remainder need to be zero

x+2=0

x=-2

substitute in the equation

3(-2)^2+k(-2)+6=0

3(4)-2k+6=0

2k=12+6

2k=18

k=9